Why doesn't the option for 120 FPS exist on a Samsung Galaxy S20 5G if it has 120 hz? (Note: By standard it has 60 hz, but you have the option within the built-in settings app to change to 120 hz.)
Devices with the minimum hardware requirements of 90Hz display refresh rate, and Snapdragon 865 or Dimensity 1100 central processing unit, can access the 90 FPS option with Smooth graphics.
You can share your feedback regarding this through https://pubgmobile.live/support if your device meets these requirements but do not have access to 90 or 120 FPS.